Pharmacophysiological study on muscle treated with calcium ionophore A23187.
Muscle treated with A23187, which raises intracellular free Ca2+ concentration, was studied to elucidate effects on membrane properties. The mean resting membrane potential was reduced; it was normally depolarized by ouabain but not significantly hyperpolarized by epinephrine and insulin. In the presence of ouabain, membrane depolarization was not provoked by insulin. The results imply a defect of active Na+-transport of the membrane after exposure to a calcium ionophore.
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000001:Calcimycin / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D003964:Diaphragm / Q000187:drug effects; D004837:Epinephrine / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D009132:Muscles / Q000187:drug effects*; D010042:Ouabain / Q000494:pharmacology; D051381:Rats; D012964:Sodium / Q000378:metabolism*
D000900:Anti-Bacterial Agents; D007328:Insulin; D000001:Calcimycin; D010042:Ouabain; D012964:Sodium; D002118:Calcium; D004837:Epinephrine